"Prepared for Darin Watschke, USFS Custer National Forest, Billings"
Includes bibliographical references [p. 19]
During the 2008 USFS Aquatic Surveys of Crooked and Sage Creek project, we sampled and assessed aquatic macroinvertebrate community integrity and diversity in relation to the Crooked Creek fish exclusion barrier completed in 2007 by comparing upstream and downstream macroinvertebrate communities. Additionally, we evaluated 35 stream sites in the area of interest potentially containing unique, species of concern (SOC) or important indicator macroinvertebrate taxa in relation to future restoration projects; only 16 of these sites contained water at the time of visit and were sampled. Six of the 16 flowing lotic sites had good habitat quality ranked by at least one of the habitat assessment methods. Five of the 16 sites were ranked slightly impaired and five moderately to severely impaired. Dry sites visited (19) were not assessed, but generally had fewer riparian and in-stream channel problems because of minimal cattle use. Overall, 112 macroinvertebrate taxa were reported from the USFS Custer 2008 assessment sites. Average macroinvertebrate taxa richness per site was 24.67, and the highest taxa richness reported was 48 at the Crooked Creek site above barrier. All sample sites within the Crooked Creek canyon showed good to excellent benthic integrity. The progression of decreasing biointegrity (as measured by the DEQ MMI) occurs as one proceeds up and out of the Crooked Creek Canyon is significant, and seems causally linked to increasing riparian degradation as cattle have access to the tributaries and mainstem of Crooked Creek